It is known that butadiene can be converted to dodecanedioic acid (DDDA) by process which involves converting the butadiene to cyclododecatriene (CDDT), reducing the CDDT to cyclododecane (CDD), oxidizing the CDD to a mixture comprising cyclodecanol (A, for alcohol) and cyclodecanone (K, for ketone) in the presence of a boric acid catalyst, and finally oxidizing the mixture of K and A to DDDA using nitric acid. In this process, the K and A mixture contains about 80-90% A and 10-20% K.
Recently, for environmental reasons, it has been proposed to perform the above reaction without boric acid, to eliminate boron-containing waste. A boron-free process for the manufacture of a mixture of cyclododecanone (K) and cyclododecanol (A) is disclosed in U.S. Pat. No. 5,892,123. When the above-described reaction is performed without boric acid, the K and A mixture contains about 10-25% A and 75-90% K. The mixture also contains undesirable epoxides and cyclododecanedione impurities. Cyclodecanedione is particularly objectionable, because it imparts a fluorescent canary yellow color to the final K and A mixture, which is further used in the manufacture of lauryl lactam and, ultimately, of Nylon 12. It can also deactivate catalysts used to convert the K and A mixture into lauryl lactam. Its presence in the K and A mixture can also impart undesirable odors to fragrance chemicals made using the mixture or pure cyclododecanone. Accordingly, there is a need for a process which can be used to convert cyclododecanedione to substances such as cyclododecanone, which do not have these undesirable effects.
Although two references (Klinova, L. L.; Patsukova, A. I.; Malygina, N. M.; Bychkova, L. N.; Egorova, L. T., Pr-vo Organ. Produktov. M. (1982) 79-84 and Chemyshkova, F. A.; Mushenko, D. V., Neftekhimiya (1976), 16(2), 250-4) disclose the reaction of cyclododecane epoxide with active nickel (i.e., nickel reduced in the presence of hydrogen) or with palladium or rhodium (metal-catalyzed isomerization to cyclododecanone), these references do not disclose the use of such catalysts to convert a cyclodecane-1,2-dione to cyclododecanone.
The use of copper or nickel catalysts for conversion of C12 alcohol or C12 alcohol/ketone mixtures to C12 ketone is known in the art. For example, U.S. Pat. No. 3,374,270 discloses catalytic dehydrogenation of C12 alcohol to C12 ketone using copper supported on an aluminum oxide carrier, U.S. Pat. No. 3,652,674 discloses the same reaction using a barium-promoted copper chromite catalyst, JP 74030827 discloses dehydrogenating C12 alcohol to C12 ketone using a nickel on kieselguhr catalyst, and JP 03115247 discloses vapor-phase dehydrogenation of the alcohol to the ketone using a copper/zinc catalyst. None of these references, however, discloses the use of catalysts to convert a C12 diketone to a C12 ketone.